scholarly journals Tree Growth and Water-Use Efficiency Do Not React in the Short Term to Artificially Increased Nitrogen Deposition

Forests ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 47 ◽  
Author(s):  
Francesco Giammarchi ◽  
Pietro Panzacchi ◽  
Maurizio Ventura ◽  
Giustino Tonon
Keyword(s):  
Water Use Efficiency ◽  
Nitrogen Deposition ◽  
Water Use ◽  
Basal Area ◽  
Co2 Concentration ◽  
N Deposition ◽  
Carbon Sequestration Potential ◽  
Sequestration Potential ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

Increasing atmospheric CO2 concentration and nitrogen deposition are, among the global change related drivers, those playing a major role on forests carbon sequestration potential, affecting both their productivity and water-use efficiency. Up to now, results are however contrasting, showing that the processes underlying them are far from being fully comprehended. In this study, we adopted an innovative approach to simulate the increase of N deposition in a sessile oak forest in North-Eastern Italy, by fertilizing both from above and below the canopy. We observed the dynamics of basal area increment, intrinsic water-use efficiency and of several leaf functional traits over 4 years, to evaluate how the added nitrogen and the two different fertilization system could affect them. We were not able, however, to detect any shift, besides a common yearly variability related to a prevailing background environmental forcing. To this end, we considered as relevant factors both the short time-span of the observation and the relatively low rate of applied nitrogen. Therefore, we stress the importance of long-term, manipulative experiments to improve the understanding of the C sequestration and mitigation ability of forests in response to increased N deposition.

scholarly journals Basal area growth, carbon isotope discrimination, and intrinsic water use efficiency after fertilization of Douglas-fir in the Oregon Coast Range

2017 ◽  
Vol 389 ◽  
pp. 285-295 ◽  
Author(s):  
Eladio H. Cornejo-Oviedo ◽  
Steven L. Voelker ◽  
Douglas B. Mainwaring ◽  
Douglas A. Maguire ◽  
Frederick C. Meinzer ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Carbon Isotope Discrimination ◽  
Basal Area ◽  
Coast Range ◽  
Oregon Coast Range ◽  
Oregon Coast ◽  
Intrinsic Water Use Efficiency ◽  
Area Growth ◽  
Use Efficiency

scholarly journals Disentangling Contributions of CO2 Concentration and Climate to Changes in Intrinsic Water-Use Efficiency in the Arid Boreal Forest in China’s Altay Mountains

Forests ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 642 ◽  
Author(s):  
Guobao Xu ◽  
Xiaohong Liu ◽  
Soumaya Belmecheri ◽  
Tuo Chen ◽  
Guoju Wu ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Water Use Efficiency ◽  
Water Use ◽  
Tree Growth ◽  
Co2 Concentration ◽  
Optimization Approach ◽  
The Past ◽  
Altay Mountains ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

Intrinsic water-use efficiency (iWUE) is affected by the balance of photosynthetic rate, stomatal conductance, and climate, along with many other exogenous factors, such as the CO2 concentration in the atmosphere (CO2atm), nutrients, and water holding capacity of the soil. The relative contributions of CO2atm and climate to iWUE are still incompletely understood, particularly for boreal forests where the climate is undergoing unprecedented warming. We combined δ13C and δ18O in tree rings from the Siberian larch (Larix sibirica Ledeb.) in Northwestern China’s Altay Mountains, which receives 190 mm in annual precipitation, to detect the drivers of long-term iWUE changes and their time-varying contributions over the past 222 years. A climate optimization approach was used to isolate the influence of climate from CO2atm influence on iWUE. We found that iWUE increased about 33.6% from 1790 to 2011, and rising CO2atm contributed 48.8% to this iWUE increase. The contributions of CO2atm and climate (drought conditions) varied during the study period 1790–2011. From 1790 to 1876, the climate was the most important factor contributing to the changes in iWUE. From 1877 to 1972, CO2atm was the main contributor; however, after 1973, the climate was again the dominant contributor to the increase in iWUE, especially during 1996–2011. During the period 1996–2011, climate substantially (83%) contributed to the iWUE increase. Our findings imply that, in the boreal forest in Northwestern China’s arid region, iWUE experienced three changes: (1) the climate dominating from 1790 to 1876; (2) CO2atm dominating from 1877 to 1972, and (3) climate dominating again during the past four decades. We observed that the relationships between iWUE and tree-ring width shifted from positive to negative from 1996 onwards. These relationship changes indicate that CO2atm-mediated effects of increasing iWUE on tree growth are counteracted by climatic drought stress and iWUE increase cannot counter the stress from drought on tree growth in China’s arid boreal forest.

scholarly journals Drought-induced mortality selectively affects Scots pine trees that show limited intrinsic water-use efficiency responsiveness to raising atmospheric CO2

2014 ◽  
Vol 41 (3) ◽  
pp. 244 ◽  
Author(s):  
Ana-Maria Hereş ◽  
Jordi Voltas ◽  
Bernat Claramunt López ◽  
Jordi Martínez-Vilalta
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Tree Mortality ◽  
Intercellular Co2 Concentration ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Growth Enhancement ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
The Impact

Widespread drought-induced tree mortality has been documented around the world, and could increase in frequency and intensity under warmer and drier conditions. Ecophysiological differences between dying and surviving trees might underlie predispositions to mortality, but are poorly documented. Here we report a study of Scots pines (Pinus sylvestris L.) from two sites located in north-eastern Iberian Peninsula where drought-associated mortality episodes were registered during the last few decades. Time trends of discrimination against 13C (Δ13C) and intrinsic water-use efficiency (WUEi) in tree rings at an annual resolution and for a 34 year period were used to compare co-occurring now-dead and surviving pines. Results indicate that both surviving and now-dead pines significantly increased their WUEi over time, although this increase was significantly lower for now-dead individuals. These differential WUEi trends corresponded to different scenarios describing how plant gas exchange responds to increasing atmospheric CO2 (Ca): the estimated intercellular CO2 concentration was nearly constant in surviving pines but tended to increase proportionally to Ca in now-dead trees. Concurrently, the WUEi increase was not paralleled by a growth enhancement, regardless of tree state, suggesting that in water-limited areas like the Mediterranean, it cannot overcome the impact of an increasingly warmer and drier climate on tree growth.

scholarly journals Photosynthetic Efficiency in Aroeira and Cedro After the Application of Salicylic Acid

2018 ◽  
Vol 10 (11) ◽  
pp. 532
Author(s):  
Maria Eunice Lima Rocha ◽  
Fernanda Ludmyla Barbosa de Souza ◽  
João Alexandre Lopes Dranski ◽  
Mayra Taniely Ribeiro Abade ◽  
Pablo Wenderson Ribeiro Coutinho ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Water Use Efficiency ◽  
Water Use ◽  
Photosynthetic Efficiency ◽  
Co2 Concentration ◽  
Photosynthetic Parameters ◽  
Fixed Amount ◽  
Schinus Terebinthifolius ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

The objective of this research was to quantify the photosynthetic efficiency of Cedrela fissilis and Schinus terebinthifolius seedlings after application of salicylic acid for eight weeks. The experimental design was completely randomized, composed of four treatments, with five replicates of 20 seedlings each. The treatments consisted of increasing doses of the salicylic acid solution: 0, 100, 200, 300 mg L-1. The solution was composed of salicylic acid, deionized water and adjuvant and applied with hand sprayer, weekly for 2 months. The parameters evaluated after the application of the acid consisted of the rate of CO2 assimilation, leaf transpiration, stomatal conductance and internal CO2 concentration, as well as water use efficiency, intrinsic water use efficiency and instantaneous carboxylation efficiency. In seedlings of Schinus terebinthifolius there was a reduction of the photosynthetic parameters and consequently a better use of water as the doses of the plant growth regulator were increased. In the seedlings of Cedrela fissilis the dose of 200 mg L-1 resulted in greater CO2 fixation per molecule of water lost and in this sense, it can be inferred that the increase in the doses of salicylic acid improved the photosynthetic efficiency, but the use of water was lower. Thus, for both species, lower doses are more recommended because there must be a balance between the fixed amount of CO2, the plant generated from photoassimilates and the amount of water lost, in order not to generate a negative potential in the plant metabolism.

scholarly journals Gas exchanges and water-use efficiency of Nopalea cochenillifera intercropped under edaphic practices

2020 ◽  
Vol 11 ◽  
pp. e3035
Author(s):  
José Thyago Aires Souza ◽  
João Everthon da Silva Ribeiro ◽  
Jucilene Silva Araújo ◽  
João Paulo de Farias Ramos ◽  
José Pereira do Nascimento ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Agricultural Research ◽  
Net Photosynthesis ◽  
Co2 Concentration ◽  
Gas Exchanges ◽  
Intrinsic Water Use Efficiency ◽  
Internal Co2 ◽  
Use Efficiency ◽  
Nopalea Cochenillifera

The Nopalea forage cactus (Nopalea cochenillifera) is the main xerophilic species cultivated in Brazil, highlighted as a compatible biological element with the semiarid environment. However, studies on its physiological aspects are still scarce. In this context, an experiment was performed in the Pendência Experimental Station, belonging to the State Company of Agricultural Research of Paraíba (EMEPA-PB), municipality of Soledade, state of Paraíba, Brazil, aiming to evaluate the gas exchanges and the water-use efficiency of intercropped Nopalea Cochenillifera plants in the soil under different edaphic managements. The treatments were distributed in randomized blocks, with three replications in a 2 × 5 factorial scheme, corresponding to the soil without and with mulch and five types of cultivation of Nopalea forage cactus, in monoculture and intercropped with forage watermelon, millet, sorghum, and buffelgrass. The analyzed variables were: stomatal conductance, transpiration rate, net photosynthesis rate, and internal CO2 concentration, besides the instantaneous water-use efficiency, intrinsic water-use efficiency, and instantaneous carboxylation efficiency. The use of soil mulch satisfactorily increased the photosynthetic rate of the forage cactus; this type of practice can aid in the productive development of the crop in semiarid zones, whereas the intercropping with buffelgrass and forage watermelon stimulated photosynthesis and the water-use efficiency.

scholarly journals Effect of phosphorus and potassium on gas exchanges of Tachigali vulgaris

2020 ◽  
pp. 1961-1969
Author(s):  
Pedro Henrique Oliveira Simões ◽  
João Olegário Pereira de Carvalho ◽  
Dênmora Gomes de Araujo ◽  
Marcos André Piedade Gama ◽  
Clenes Cunha Lima ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Block Design ◽  
Co2 Concentration ◽  
Potassium Fertilizer ◽  
Physiological Processes ◽  
Randomized Block Design ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
Phosphorus And Potassium

Tachigali vulgaris L. G. Silva & H. C. Lima is a pioneer species with great potential for reforestation. The inadequate supply of phosphorus and potassium results in nutritional disorders, requiring nutritional complementation. This study aimed to evaluate the effect of phosphorus (P) and potassium (K) doses on Tachigali vulgaris gas exchange. Three doses of P (0, 26.7 and 53.5 kg-1 ha) and three doses of K (0, 50 and 100 kg-1 ha) were applied in a 3x3 factorial scheme as randomized block design. The data were submitted to analysis of variance using the Tukey 1% test and Pearson's linear correlation test. Potassium fertilization provided increases of approximately 30% in the rate of liquid photosynthesis (PN). Stomata conductance (GS), internal CO2 concentration (Ci), perspiration (E), instantaneous caboxilation efficiency (ΦC), water use efficiency (EWU) and intrinsic water use efficiency (iEWU) were also favored at dose of 78.2 g kg-1 K, suggesting their role in regulating essential physiological processes for plant growth. The highest PN values were observed with application of 33.1 g kg-1 P and 78.2 g kg-1 K, with rates of 4.28 and 4.86 μmol CO2 m-2 s-1, respectively, which also occurred with E, ΦC, EWU and iEWU. It was observed that P exerted antagonistic effects on K absorption, which may also have impaired Mg2+ absorption due to the fact that Ca2+ is an accompanying ion of potassium fertilizer

Increasing intrinsic water-use efficiency over the past 160 years does not stimulate tree growth in southeastern China

2018 ◽  
Vol 76 (2) ◽  
pp. 115-130 ◽  
Author(s):  
G Guo ◽  
K Fang ◽  
J Li ◽  
HW Linderholm ◽  
D Li ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Tree Growth ◽  
Southeastern China ◽  
The Past ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency
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